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Reply To: | TechNet E-Mail Forum. |
Date: | Mon, 18 Oct 1999 12:08:11 -0700 |
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Ken,
If the microBGA has microvias think about the "Z" axis
expansion. The PCB would see far more "Z axis" expansion
for a through hole as opposed to a microvia(Proportionately
speaking). Class 3 criteria generally is for life support,
super high rel (space to the desert in one final swoop),
...etc. I do believe the annular ring callouts were
based on round robin testing of actual test samples.
So where does your product fit in? Class 2 or class 3?
Groovster
-----Original Message-----
From: Ken Patel [mailto:[log in to unmask]]
Sent: Monday, October 18, 1999 11:52 AM
To: [log in to unmask]
Subject: [TN] Annular ring requirement by IPC
I have the basic question:
Why do we need annular ring on inner layers? If the answer is no then why
IPC is asking for 1 mil annular ring on Class 3 products. The problem arisen
due to microBGA application.
re,
ken patel
______________________________________________________
Ken Patel Phone: (408) 490-6804
1708 McCarthy Blvd. Fax: (408) 490-6859
Milpitas, CA 95035 Beeper: (888) 769-1808
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